The present invention relates to a lock connector which can reliably detect that a pair of connector housings are electrically connected to each other by way of short-circuiting in the locked state.
A known lock connector of the foregoing type is shown in the disassembled state in FIG. 11. Referring to the drawing, a male connector housing 1 is fixedly mounted on a base plate 2 and includes a pair of lock detecting electrodes 4a and 4b on the opposite side parts of a positioning piece 3 having an inverted T-shaped cross-sectional contour as shown in FIG. 12. On the other hand, as shown in the drawing, a female connector housing 5 includes a substantially U-shaped short circuit electrode 6 of which one end is projected to come in contact with the opposite side parts of the positioning piece 3 and of which other end is connected to a main body of the female connector housing 5. Incidentally, to assure that the short circuit electrode 6 is not brought in contact with the lock detecting electrodes 4a and 4b by curvedly bending the short circuit electrode 6 in the upward direction at the beginning time when the short circuit electrode 6 is fitted into the connector housing 1 on the male side, a pair of guide projections 3b are formed on the opposite sides of an upright standing partition wall portion 3a of the positioning piece 3.
On the other hand, a flexible lock piece 7 is formed integral with the female connector housing 5 on the upper surface of the latter, and a protuberance 7a is formed on the upper surface of the flexible lock piece 7. In addition, an engagement hole 1a adapted to be engaged with the protuberance 7a of the flexible lock piece 7 is formed on the upper surface of the male connector housing 1.
With such construction, as the flexible lock piece 7 on the female connector housing 5 is inserted into the male connector housing 1 while it is curvedly bent, the short circuit electrode 6 is curvedly bent in the slantwise upward direction by the guide projections 3b as shown in FIG. 13. When the female connector housing 5 is completely inserted in the male connector housing 1, the protuberance 7a of the flexible lock piece 7 is engaged with the engagement hole 1a of the male connector housing 1, and at the same time, the short circuit electrode 6 is parted away from the guide projections 3b and comes in contact with the lock detecting electrodes 4a and 4b as shown in FIG. 14. The lock detecting electrodes 4a and 4b are electrically connected to a detecting circuit (not shown) by way of short-circuiting, and when the detecting circuits detects that short circuit takes place with the lock connector, it determines that the connector housing 1 on the male side and the connector housing 5 on the female side are firmly held in the locked state relative to each other.
With the conventional lock connector constructed in the above-described manner, to assure that detection reliability is improved, it is necessary that the time when the protuberance 7a of the flexible lock piece 7 is engaged with the engagement hole 1a on the male connector housing 1 correctly matches with the time when the short circuit electrode 6 comes in contact with the lock detecting electrodes 4a and 4b. However, as far as the aforementioned conventional lock connector is concerned, many difficulties appear when it is practically produced, because a molding accuracy should be improved, and moreover, an accuracy on the position where the short circuit electrode 6 is disposed should be elevated.
Further, since elasticity of the flexible lock piece 7 molded integral with the female connector housing 5 is increasingly degraded as time elapses, there arises a malfunction that the female connector housing 5 is vibratively received in the male connector housing 1. Once the female connector housing 5 is vibratively received in the male connector housing 1 in that way, the short circuit electrode 6 is incorrectly brought in contact with the lock detecting electrodes 4a and 4b, resulting in the locked state between both the connector housings 1 and 5 being erroneously detected. When a separate spring is disposed in the lock connector so as to cope with the foregoing problem, this leads to the result that the number of components constituting the conventional lock connector is undesirably increased.
Furthermore, it is necessary that the male connector housing 1 is constructed such that the protuberance 7a formed on the upper surface of the flexible lock piece 7 is received in the engagement hole la formed on the upper surface of the male connector housing 1 when the female connector housing 5 is fitted into the male connector housing 1. This leads to the result that the male connector housing 1 is unavoidably enlarged in dimension.